You should also to be able to spawn your own monsters. The correct format is as follows:
#spawn name race level material hp gender class weapon# merchantID
Make sure the desired class is available for the zone you are in or else you will get a human (default). Here is an example to spawn a level 35 Spectre wizard in Oasis:
#spawn a_spectre 85 35 0 2000 2 12 0 0
I haven't been able to get the weapon# to work, and the merchantID only seems to work with merchants and bankers which makes sense
These spawned mosters don't actually accomplish anything, but you can fight them.
You can also spawn monsters if you have npctype mosters created in the database.
You must be a priveleged user+ in order to use these advanced commands, which are in the readme.txt file...have fun and experiment.